a. Field of the Invention
The present invention pertains generally to computer databases and specifically to the synchronization of databases that have metadata.
b. Description of the Background
Synchronization of databases comprising raw data and derived metadata is complicated when the derived metadata are not current with the raw data.
In many databases, metadata derived from raw data is a useful tool. The metadata may simplify searching, sorting, and gross manipulation of the raw data especially when the metadata are organized to facilitate such manipulation. Further, the metadata may comprise orders of magnitude less data than the raw-data. For example, a database of documents may contain raw data containing text, figures, and numerical data, and may also include metadata such as the title, chapter headings, author, or other metadata that are derived from the raw data.
In such a database, changes to the raw data would generally be reflected in the metadata. Before the metadata is updated, and when the raw data do not correspond with the metadata, the metadata is ‘stale.’ Problems arise when synchronization occurs while metadata is stale, because stale metadata may be synchronized between the databases, leaving the synchronized databases in an inconsistent state.
It would therefore be advantageous to provide a system and method for synchronizing databases having derived metadata wherein the synchronization may occur at any time, without regard to the ‘staleness’ of any data. It would be further advantageous if such a system were robust and consumed a minimum amount of computing and communication resources.